Pneumatic door-check



l (N0 Model-J 2 Sheets-Sheet I.

V G. S. PERKINS.

PNEUMATIG DOOR CHECK. No. 360,042. K Patented Mar. 29, 1887.

N. PETERS, mammal. wnnmgm. uA c.

'(No Model.) 2 Sheets-Sheet 2.

G. S. PERKINS.

PNEUMATIG DOOR CHECK.

Patented Mar. 29, 1887.

1.1 h/y/A Ntra STATES lArnNr einen.

GUSTAVUS S. PERKINS, OF HARTFORD, CONNECTICUT.

PN EUMATIC DOOR-CHECK.

SPECIFICATION forming part of Letters Patent No. 360,042, dated March29, 1887.

Application filed August 2, 1886. Serial No. 209ml. (No model.)

.To all whom, 'it may concern:

Beit known that l, GUsTAvUs S. PERKINS, of Hartford, in the county ofHartford and State of Connecticut, have invented a certain new anduseful Improvement in Pneumatic Door-Checks, of which the following is afull, clear, and exact description, whereby a person skilled in the artcan make and use the same.

My improvement relates to that class of door-checks in which theelasticity of air when confined in a chamber is made use of as a bufferor cushion to prevent the slamming of a door in closing under theimpulse of a spring.

The object of my improvement is mainly to provide a device of this classwith a peculiar valve or vent that automatically regulates and controlsthe movement of the air out of and into the chamber in a cylinder' infront of the piston.

To this end my improvement consists in a cylinder having practicallyair-tight head in combination with a piston that bears the au` tomaticseltregulating valve; and it further consists in the combination ot' acylinder with contained piston, and the peculiar' levers that connect adoor and its frame to such parts, as more particularly hereinafterdescribed, and pointed out in the claims.

Referring to the drawings, Figure lis a front view of one form-of myimproved device as adjusted in position for use. Fig. 2 is a view inhorizontal section through the door-check on the plane denoted bytheline x a: of Fig. l. Fig. 3 isa detail view in section on the sameplane, sh owing the part-s extended by the opening ofthe door. of thepiston. Fig. 5 is a detail rear View of the piston. Fig. G is a detailview in crosssection through the piston and valve on plane denotedbyline y i/in Fig. 4. Fig. 7 is a detail'view ofthe front end of amodified form of piston and valves. Fig. S is a detail view incross-section through the latter form of piston and valves, showingcomparative views illustrating` the operation of the valves.

In the accompanying drawings, the letter a denotes a door-i'rarne; Z), adoor, and c the cylinder of the door-checlr. rIhis cylinder ispreferably a metallic tube having iirmly screwed or fastened to one endthe back head, which is pivotally connected to a stand, c, the latterhaving the foot e', through which screws are driven to fasten the standto the jamb of the Fig. et is a detail front view door or to the door.In the drawings the cyl inder is pivotally connected at the back head tothe door-jamb.

rl`he letterf denotes the front head of the cylinder, that is firmlysecured thereto, as by means of ascrew-thread, and through the center ofthis front head passes the piston-rod g, on the inner end ot which isscrewed the piston g. Vithin the cylinder, and between the back oi" thepiston and the front head, is arranged a spiral spring, h, seated withone end pressing against the piston and the other against the follower7i', that is seated on the ends of screws that are bornein threadedsockets in the front head, and preferably extend through it, so thattheir outer ends are accessible for the purpose of adjusting theposition of this follower with relation to the fronthead, so as toincrease or decrease the tension of the spring 7i without removing thehead from the cylinder. The outer end of this piston-rod g is pivotallyconnected to the lever k, that is a bent lever pivotally connected atils angle to the stand l, and at its other end to the tie-rod m. In theform shown this tie rod is pivoted to the guiderod n, and, to theconnecting-arm o by a common pivot at the meeting point of these parts,the guiderod being pivoted to lugs l on a stand, Z, at a point betweenthe points ot' connection of the stand l and bent lever 7a and the bentlever and tie rod m, these three points being about in line with cachother when the parts are in their normal position, as seen in Fig. l.

The connecting-arm ois pivoted to theY bracket 1), that is secured tothe door b, and when the latter is opened the arm pushes tle tie-rod atits outer end, which in turn pullsl on and rocks the bent lever, andthus draws the piston forward in the cylinder, compressing the closingspring, whether the latter is inclosed in the cylinder or is attached tothe door at some other point.

By means ofthe bent lever, the guide-roda, and tic-rod m the travel ofthe piston in a given sizeof cylinder is reduced to a minimum. (Anexamination of the position of guide-rod n and tie-rod min Fig. 3 willshow this.) The force of the compressed spring when the door is openedis thus used to the best advantage, and the door is prevented fromtraveling faster in closing than the piston travels in the cylinder, andit also more eli'ectuallyprevents the door from slamming'than when thepistonrod is pivoted directly to the tie-rod. It has been found byexperiment and somewhat ex tended use of this device that the forcerequired to first move the door in opening in creases to about twicethat amount until the door reaches an angle of sixty degrees and thenthe force decreases, but not to a degree to prevent the spring fromstarting the door very forcibly in closing.

At no time in the movement of the several levers and connecting partsdoes the pull of the spring upon the piston-rod lie in a line' throughthe pivots or over the center/7 as is the case in several prior devices,and thus there is no pause in the closing movement of the door. Thedecreased play of the piston enables the cylinder to be made muchshorter and cheaper than in prior devices having a spring ofthe samepower and a cylinder of the same diameter.

The follower h', that is arranged between one end of the spring and thefront head of the cylinder,is supportethpreferably, on screws h,that areadjustable in sockets in the follower, and have shoulders bearingagainst the inner side of the front head,f. The tension of the springmay be easilycontrolled by this device.

There is no provision made for the passage of air into or out ofthecylinder c. In fact, the latter is substantially air-tight; but thepiston g is provided with a valve, q, that provides for the passage ofair from one side to the other of the piston as it moves forward andback in the cylinder. This valve q has a broadened head, q', lying on'the front side of the piston, and held with its stem q within thechamber 1 by the pressure of theI spring r. Vithin the chamber ,.r, thatis open through'to the back of the piston, is seated a spiral spring,1', with one end thrusting against a shoulder or lug within the chamberand the other against the valve, so as to hold it in its normalcondition between the two springs and slightly raised from its seat. Inthis condition, when the door to which this device is connected isopened, the piston moves toward the front head of the cylinder, the airpassing quite freelyv through the valve in the piston, and offeringpractically no resistance to such forward movement of the piston. Assoon as the return movement of the piston is begun,

as under the impulse oi a spring, any quick movement of the pistoncauses the valve q to close upon its seat and prevent the passage of airfrom the front to the back side of the piston.

The valveseat is preferably provided with a relief-opening, S2, whichconsists of avery small channel in the face of the valve or seat, thatallows asufcient quantity of air to leak through to relieve the pressureon the back of the valve, due to the compression of the air in front ofthe piston, and as soon as this pressure of the compressed air is lessthan the pressure of the spiral spring in the chamber the valve opensandallows the air to pass more freely through it to the other side of thepis ton, which then continues its movement, and the door closes quietly.

Instead of providing the valve q or its seat with the relief-openingdescribed, I may use a separate relief-valve, s, located at anotherpoint in the piston, and thismay consist of' a valveseat formed on theback of the piston, into which the valves is seated under the pressureof the spring s. The office of the reliefvalve is the same as that ofthe relief-opening. In order to provide for thetight packing of thepiston, I use a cup-packing, t, of suitable material, as leather,secured to the piston by a disk-shaped clamp that is screwed upon anextension of the pistonrod, that is perforated for the free passage ofthe air. p

The piston may obviously be packed in any other convenient way and theclamp secured by other means than screwing it onto the eX- tension ofthe piston-rod; but the latter is preferable.

I claim as my'i-nvention- 1. In a door-check of the within-describedclass, the combination of the cylinder with pivot-bearings on its backhead, the cylindersupporting stand e, the piston and connectedpiston-rod, the bent lever and its supportingstand, with one end ofsaidlever pivotally connected to the piston-rod and the other to a tie-rod,the guide-rod n, and connectingarm with its supportingstan'd, thetie-rod, guiderod, and connecting-arm being united by a common pivot,all substantially as described.

2. In a door-check of the within-described class, in combination withthe cylinder andits connected piston and rod, a bent lever pivotallyattached to the frame or casing of a door,to which part the cylinder isalso connected, and having its outer ends pivotally connected to thepiston and a tie-rod, respectively, and a guiderod, also pivoted to astand, all substantially as described, and for the purpose se forth.

43. In a pneumatic door-check, in combination, a cylinder with closedend, and a piston movable within the cylinder,with its outer1 edgehaving an air-tight packing, and the balanced valve borne by said pistonto permit `the passage of air through the piston, all substantially asdescribed.

4. In a pneumatic door-check, a cylinder, c, and a piston, g, bearingthe valve q, having a relief-opening, all substantially as described.

5." In a pneumatic door-check,y in combination, a cylinder, c, and apiston, g, having the valve g balanced between the springs r and r2, andhaving a relief-opening, all substantially as described.

6. In a pneumatic door-check, in combination, a cylinder, c, and apiston, g, having the IOO rio

balanced valve q, and a reliefvalve, s, all substantially as described.

GUSTAVUS S. PERKINS.

lVitnesses:

Guns. L. BURDETT, H. It. WILLIAMS.

